Understanding Terpenes: Humulene
Humulene, also known as α-humulene, is a relatively common terpene that is produced by many plants other than cannabis. This encompasses basil, the hops used to brew beer, clove, and many types of wood. Humulene conveys an overall herbal aroma that is reminiscent of earth, musk, or spice.
The exact scent achieved by a cannabis plant depends on the nuanced composition of its terpene profile(the presence and ratios of all of the terpenes that it produces). Popular consumer cannabis products in many legal jurisdictions provide a terpene profile via a document called a Certificate of Analysis (CoA), which is provided by an independent testing laboratory (and bundled with the product packaging or available upon request).
From the perspective of medicinal efficacy, humulene has been found to reduce inflammation while also acting as an antibacterial agent. It has also demonstrated significant anti-cancer efficacy for major forms of the common disease, including breast cancer.
Molecular Sibling to BCP
Prior to bearing its current name, humulene was labeled by scientists and chemists as alpha-caryophyllene(α-caryophyllene). This was for good reason. Humulene is produced in greater volumes in cultivars of cannabis that also feature richer levels of the terpene beta-caryophyllene(BCP).
This is logical, given that the two terpenes feature the exact same chemical formula, but a different molecular structure. The same is true for other plants in nature in terms of the occurrence of both BCP and humulene. Basil, clove, and sage also produce ample amounts of these two similar terpenes.
A 2016 research study entitled “β‐caryophyllene and β‐caryophyllene Oxide—Natural Compounds of Anticancer and Analgesic Properties” that was published in the journal Cancer Medicineexplored the ability of terpenes such as BCP and humulene to effectively treat cancer, specifically investigating its efficacy for breast cancer (the most common form of the disease).
Reported the study, “α‐humulene exhibited significant antiproliferative activities against…[cancer] cells. Moreover, the cytotoxic [toxic] effect of not only α‐humulene, but also iso‐caryophyllene, was enhanced by BCP.” The study revealed that humulene and iso-caryophyllene were most effective at combating cancer when paired with BCP. The researchers reported that these molecules “were more effective in [the] reduction of…human breast cancer cell line proliferation [when acting together] than when used separately.”
A 2007 study entitled “Anti-inflammatory Effects of Humulene and Caryophyllene Isolated from the Essential Oil of Cordia Verbenacea” that was published in the European Journal of Pharmacologyinvestigated the anti-inflammatory properties of BCP and humulene. The researchers reported, “Our results revealed that oral treatment with both compounds displayed marked inhibitory effects [reductions] in different inflammatory experimental models in mice and rats.”
The study found the anti-inflammatory efficacy of humulene and caryophyllene to be “comparable to those observed in [animals treated with] dexamethasone,” a popular control drug. The study’s researchers concluded that terpenes such as humulene and BCP display promise in the treatment of a variety of diseases that share the root cause of inflammation. “These findings indicate that alpha-humulene and trans-caryophyllene, derived from the essential oil of C. verbenacea, might represent important tools for the management and/or treatment of inflammatory diseases.”
A 2006 study entitled “Composition and Antibacterial Activity of Abies Balsamea Essential Oil” that was published in the journal Phytotherapy Researchexplored the ability of humulene, as found in balsam fir oil, to act as an antibacterial in the treatment of two common strains of bacteria: Escherichia coli and Staphylococcus aureus.
The oil employed in the study contained several terpenes, not all of which were effective as antibacterial agents. However, alpha-pinene (α-pinene), beta-caryophyllene, and humulene were found to effectively exert significant antibacterial activity. Interestingly, the study found that the terpenes beta-pinene (β-pinene) and delta-3-carene were ineffective against these two particular bacterial strains.